462 



LIVER. 



[CHAP.XXXIII. 



vein, and both tending towards the notch in the posterior border 

 which lodges the vena cava ; these divisions, however, are both of 

 them on the surface only, and are rather vestiges of the imperfect 

 conditions of fcetal existence, than of value in the study of the 

 physiological anatomy of the gland. 



On the under surface of the liver, is observed a groove passing 

 off from the longitudinal fissure, transversely, for a certain distance, 

 on the surface of the right lobe, and lodging the biliary ducts, the 

 sinus of the vena porta, the hepatic artery, with lymphatics and 

 nerves, all enveloped in areolar tissue, called the capsule of 

 Glisson, and brought to this transverse fissure between the layers 

 of the gastro-hepatic omentum. From this groove, there extends 

 throughout the substance of the organ a series of tubular passages, 

 so numerously ramified and uniformly distributed, that no part 

 whatever of the hepatic substance is at a greater distance from 

 them than about the thirtieth of an inch. These are called the 

 portal canals (fig. 216), so named by Mr. Kiernan, because they 

 lodge the branches of the portal vein, from which the plexus of 

 capillaries surrounding the biliary-cells takes origin. The portal 

 canals also lodge the bile-ducts, which are thus conducted to that 

 aspect of the mass of bile-cells, where the capillary plexus com- 

 mences. The same canals also convey the hepatic artery with the 

 lymphatics and nerves of the liver. 



On the posterior border of 

 the liver already referred to, is 

 a deep groove placed obliquely, 

 the fissure for the inferior vena 

 cava; from this there penetrate 

 the substance of the organ, 

 another series of ramified tubu- 

 lar passages, which are com- 

 pletely occupied by a nearly cor- 

 responding number of branches 

 of the hepatic veins, or vence cavce 

 hepaticce, which open into the 

 vena cava. These canals, called 

 by the same distinguished ana- 

 tomist, hepatic venouscanals, are 

 so distributed throughout the 

 organ that some part of them 

 comes within -^ of an inch of every portion of its substance, and 

 they are intermediate to the ramifications of the portal vein. The 



Fig. 216. 



A transverse section of a small portal canal and 

 its vessels, after Kiernan. 1. Portal vein. 2. Inter- 

 lobular branches. 3. Branches of the vein, also 

 giving off interlobular branches, termed by Wr. 

 Kiernan vaginal branches. 4. Hepatic duct. 5. 

 Hepatic artery. 



